Exemplary embodiments relate to nonvolatile memory devices, and more particularly, to flash memory devices.
Generally, nonvolatile memory devices can electrically erase data and program data. The nonvolatile memory device may store data even when a power supply is interrupted. The use of a nonvolatile memory device in various fields may be increasing.
The nonvolatile memory devices may constitute various cell transistors and may be classified into a NAND type and a NOR type according to a cell array structure. A nonvolatile memory cell transistor of NAND type may realize a benefit of a higher integration and a NOR memory cell transistor of NOR type may realize a benefit of a higher speed.
A NAND type device may be advantageous regarding integration due to a cell string structure that provides multiple memory cell transistors that may be serially connected to one another. Also, data stored in memory cell transistors may be simultaneously changed in a NAND type nonvolatile memory device, which may result in a speed of updating data of the NAND type nonvolatile memory device that is faster than that of the NOR type nonvolatile memory device. A NAND type nonvolatile memory device may be used in a portable electronic device having need of mass storage such as a digital camera or a MP3 player because of a high integration and a high speed of updating data.
Benefits from improvements of NAND type nonvolatile memory devices may be continuously sought after.